The Pro was a mercenary hired by Carolyn Trainer when she operated as Doctor Octopus to kill a business rival named Jason Tso. Using a pair of explosives tagged to two of Tso's employees the Pro entered the building and ended up fighting Ben Reilly who worked for Tso as a security guard. Momentarily evading Reilly the Pro found Tso and contacted Doctor Octopus who wanted to watch her rival die. Before he could finish the job the Reilly returned as the Scarlet Spider and the Pro decided to use his appearance as an excuse to up his fee. Tanner agreed but before he could kill Tso he was webbed in a cocoon and thrown out the window.
Sometime later the Pro finished the job and killed Tso when he and his security forces led a counter attack on Trainer.
The Pro returned when J. Jonah Jameson offered a $100,000 reward for a skeleton photographed with Spider-Man and wearing the same costume. Ambushing Peter Parker the Pro slapped an explosive collar around the photographers neck and forced him to drive to where the skeleton was buried. After digging up the corpse the Pro released Parker and left only to be attacked by Spider-Man who used a web line to drag him from his car.
Unfortunately the Pro wasn't the only person hunting for the body and had been tracked by a group of villains led by the Beetle and consisted of Boomerang, Jack O'Lantern, Scorpia and the Shocker. After stealing the skeleton from Spider-Man (who was engaged in fighting Jack O'Lantern) Shocker tried to escape but was quickly shot with a tranquiliser by the Pro but failed to retrieve the body, with the Beetle taking possession of it. Taking out Boomerang and Scorpia with a pair of grenades as they covered the Beetle's escape the Pro threatened to shoot the criminal if he didn't' give up the body. When the Beetle refused the Pro was blindsided by Spider-Man who hit him with a shovel and taken to prison with the rest of the villains.
The Pro had an unusual arsenal that contained but presumably wasn't limited to; tranquilizer darts, fusion grenades explosive collars and discs. He also carried a pair of silenced pistols.